Like any modern high school, 21 Jump Street is a bit too crowded for its own good. Every character is a caricature, looking to steal their scenes and hold their ground. The film has the trademark rhythm of on-set riff sessions being whittled down to a manageable length, and several supporting players would appear to have once had more than a scene or two apiece with which to get their laughs. Of course, that would only be a substantial problem if 21 Jump Street didn’t turn out to be – for the most part – one damn funny comedy.

From the start, Deputy Chief Hardy (Nick Offerman, one scene) dryly explains how “the guys in charge are out of original ideas and find themselves forced to recycle old programs.” Thus, suitably juvenile underachievers Schmidt (Jonah Hill) and Jenko (Channing Tatum) are assigned to the eponymous undercover operation in order to prevent the spread of a new drug, H.F.S., through the halls of squeaky-clean Sagan High. Captain Dickson (Ice Cube) makes the rules clear: don’t get expelled, don’t sleep with anyone, infiltrate the dealers and find the supplier.

Naturally, this is easier said than done. A tubby loser seven years earlier, Schmidt dreads returning to the persecution of his adolescence; meanwhile, Jenko finds himself facing a redefined social paradigm in which jerky jocks now rank beneath the goody-goody, eco-friendly types led by Eric (Dave Franco). Worse yet, the wonder cops have confused their own false identities, which sees the former tackling track and theater with the cool crowd while relegating the latter to math, science and an all-around geekier walk of life. The scenario sees Hill playing to his sarcastic strengths, while Tatum gets to tweak and toy with his boy-toy persona.

The result is a cheeky inversion of the usual teen movie blueprint in addition to serving as a knowing embrace of the inherent silliness of tossing plainly adult post-graduates into a high school environment and expecting nobody to notice or care all that much. As written by Hill and Michael Bacall (Project X, Scott Pilgrim vs. the World), nigh every scene of 21 Jump Street addresses the divide between the past and present with playfulness, whether it’s the flipped dichotomy between the one-time alpha male and the long-time dweeb, the goofy notion of updating a straight-faced '80s TV show into an all-out present-day lark or the idea that the high school experience remains the same no matter how its students (and their culture) transform.

The tone adapted by directors Chris Miller and Phil Lord (2009’s goofy-brilliant Cloudy with a Chance of Meatballs and the cult cartoon “Clone High”) is a proudly juvenile one, treating the material as something of a post-modern playground without relying solely on winks to inch the film past its requisite conflicts (ex: Schmidt can never close the deal with either perps or ladies; Jenko can’t even recall his Miranda rights). It’s the little touches that go far. When our officers wind up in a highway chase, they find themselves continually disappointed by the lack of Big Explosions; when they pull up to prom, they let loose their own doves for faux-dramatic effect. Cruder touches only overwhelm the general air of irreverence on occasion, with earlier innuendos feeling like easy shots and a climactic gag involving a grisly redefinition of oral endeavors indeed earning a gag itself.

While one might feel that Miller and Lord could have used a dose of the discipline essential to their animated projects, they fill the frame with tiny touches (mind the off-campus billboards; the world’s worst prom theme is harder to miss) and capable comedians. Rob Riggle as a blustery coach, Chris Parnell as a self-important drama teacher, Jake Johnson as a fed-up principal, Ellie Kemper as a science teacher with the hots and then some for Jenko – they’re all about as hilarious as can be while barely being there. With Jenko falling out with Schmidt, Schmidt falling for classmate Molly (the utterly adorable Brie Larson) and Capt. Dickson breathing down both of their necks, there are already plenty of hijinks to go around, and that’s not even mentioning a couple of cameos…

The local color is welcome, though, while the third act pays off in spades and the perfectly bombastic end credits set Eisensteinian film theory figuratively aflame with a lit fart. Without treading too much of the same ground as Hot Fuzz, the whole crew makes clear their affections for action cinema, trashy television and the YouTube generation alike while having fun at the expense of all three. When raiding the police department’s evidence lock-up for party supplies, Schmidt suggests that Jenko grab a pound of pot rather than a pound of cocaine, clarifying that “we want to show them a good time, not ruin their lives.” It’s fair to say that 21 Jump Street not only shares that sentiment, but ultimately succeeds in that respect.